A power strip is a block of electrical sockets that attaches to the end of a flexible cable, allowing multiple electrical devices to be powered from a single electrical socket. It is used where there are more electrical devices in proximity than available wall outlets. By understanding the proper uses and limitations of power strips, you can stay safe from potential electrical hazards caused by their misuse. Be aware of the following dangerous or improper conditions:
This refers to interconnecting multiple power strips and/or extension cords. Such an arrangement violates National Electrical Code (NEC) and Occupational Safety and Health Administration (OSHA) regulations because the strip or wall receptacle may become overloaded, resulting in failure or fire.
Permanently Secured Power Strips
A power strip should not be “permanently secured to building structures, tables, work benches or similar structures,” according to the Underwriters Laboratories (UL), or routed through walls, ceilings, floors or similar openings.
This is defined as wiring used for a period greater than 90 days, according to the U.S. Office of Compliance.
Wound or Knotted Cords
This can permanently damage the cords. Power strip cords should be straight while in use.
Cords that are too long present a trip hazard. According to the UL, “The length of the power-supply cord, as measured from the outside surface of the enclosure of the relocatable power tap to the plane of the face of the attachment plug, should not exceed 25 feet (7.62 m) nor be less than 1.5 feet (0.46 m).”
This sticker describes the power strip as a “relocatable power tap.” Unlisted items have not been tested for safety and may contain defects such as insufficient protective coating over the wires.
Hot to the Touch
If your electrical device is hot to the touch, be sure to check the power strip. If the power strip also feels hot, unplug it immediately.
May result in fire or electrocution, and may be caused by the following unsafe conditions:
- One wall receptacle serves multiple high-use power strips
- The power strip serves an excessive number of appliances
- The power strip serves high-voltage items not intended to be plugged into ancillary power sources (like refrigerators, microwaves, or space heaters)
Plugs should not hang out of the receptacle and must be inserted fully so that no part of the metal prongs is exposed.
If the grounding prong has been broken or cut off to fit into an ungrounded electrical receptacle, immediately remove it from service.
Discard any cords with exposed wires, cracks, or splices, and cords that have been melted, burned, frayed, discolored, or otherwise damaged.
Limited Air Circulation
Do not place a power strip in an area where air circulation is limited, such as beneath carpet or behind furniture, because it may lead to overheating.
Water can conduct electricity, so using a power strip in a moist environment may lead to electrocution.
While power strips are designed to distribute electricity, they do not regulate power flow or block electrical spikes or surges. Surge protection is incorporated into some power strips, but it should never be assumed that a power strip offers surge protection without inspecting the unit for the proper UL designation. The misconception that power strips are also surge protectors can lead to costly damage to electrical equipment during a power surge.
As with all types of extension cords, power strips should be used sparingly and temporarily. They are best used with small appliances and electronics and are not a substitute for a permanent wall outlet. By observing their improper use, you can keep yourself and others safe from potential shock or fire hazard.